Apparatus for sealing filled bags

ABSTRACT

The present invention relates to an apparatus for filling bags with a material and for sealing them, and it can carry the bags in a direction of a bag thickness. A first feature of the present invention resides in that, in the case that the bags are arranged between a pair of chain conveyors disposed in parallel vertical planes, they are gripped by plural pairs of grippers mounted on a pair of axes extending through each rectangular parallelepiped carrier. Further, a second feature of the present invention is that the apparatus according to the present invention is equipped with nozzles for introducing a compressed gas into the bags and pressure gauges for measuring a pressure within the bags in order to detect whether or not each bag is normally gripped by the grippers. Furthermore, another feature of the present invention is that a return pipe is fixed to a filling device so that the filling material may be returned to a storage tank, without being discharged therethrough, by closing the filling nozzle. Still another feature of the present invention is that seal bars for sealing the bags are covered with a heat-resistant cloth, and the cloth is sent out in turn to maintain uniform sealing conditions.

This is a division of application Ser. No. 620,887 filed June 15, 1984,now U.S. Pat. No. 4,608,803.

FIELD AND BACKGROUND OF THE INVENTION

The present invention relates to an apparatus for filling bags with amaterial and for sealing them.

The apparatus for filling the bags has already been suggested in U.S.Pat. No. 4,108,300. Each bag used on this apparatus comprises a laminateof a plastic film over a paper or an aluminum foil sheet and ispreviously sealed along three edges thereof, as shown in FIG. 1 attachedhereto. Further, the bag 1 may be a gusseted bag wherein its bottom isfolded in a gusset style so as to be capable of standing by itself.

Such an apparatus is shown in FIGS. 2 and 3. A pair of chain conveyors 2which are disposed in parallel vertical planes is supported on fivepairs of sprockets 3. Each pair of the sprockets is mounted on an axle4. Reference numerals 5 and 6 are a motor and an index devicerespectively, and the axles 4 can be intermittently rotated thereby.Grippers 7 are mounted at equidistant intervals on the chain conveyors 2and are adapted to grip upper portions of the bags 1. Numerals 8 and 9are rails for guiding the grippers 7 and a magazine for stocking thebags 1 respectively. A bag taking out member 10 serves to take out thebags 1 from the magazine 9 one by one and to transfer them to regionsbetween the opposite grippers 7, 7. Numeral 11 is a bag opening memberand possesses known vacuum cups by which the bags 1 gripped between andby the grippers 7, 7 are opened. At this time, the opposite grippers 7,7 approach to each other so as to assist the bags 1 in opening, and theopened bags 1 are carried while kept opened. Numeral 12 is a fillingdevice for a material and numeral 13 is a sealing device for the bags 1.The bags 1 which have been filled with the material and have been sealedare then discharged as bag products 1a through a belt conveyor 14.

It will be understood that the efficiency of such an apparatus forfilling the bags can be improved by carrying the bags 1 along two ormore carrying lines. However, the attempt to carry the bags 1 along aplurality of the carrying lines in the shown apparatus is not sodifferent from a combination of a plurality of the same apparatuses,though the motor 5 and a link mechanism for the bag taking out device 10can be utilized in common.

In addition, in the case that the apparatus is run at a high speed, aninsecure bag taking out operation or an insecure bag grip of thegrippers will be brought about sometimes, which fact will lead to aninaccurate bag grip between the grippers At this time, the work of thematerial filling must be interrupted. In the conventional apparatuses,however, any mechanism for judging whether or not the bags are surelygripped is not equipped, and there has not been suggested any method forfilling, with the material, all the bags on the plural carrying linesexcept one bag.

SUMMARY OF THE INVENTION

An object of the present invention is to detect whether or not the bagsare securely gripped by the grippers, in order to prevent the materialfrom contaminating the apparatus when the insecurely gripped bag or thebag not gripped is filled with the material.

Another object of the present invention is to provide a fillingapparatus which can usefully function when the filling of the materialmust be interrupted. Therefore, where the bags are carried along theonly one carrying line or where a filling device is independentlyprovided in the apparatus, the present invention is not necessary,because in such a case, the work of the material filling can beinterrupted merely by causing the filling device alone to stop. Thepresent invention contemplates halting only one of the plural fillingdevices, when needed, while they are run by the use of an only one linkmechanism.

Still another object of the present invention is to provide an apparatussuitable for the transit of the bags along plurally arranged carryinglines. The apparatus of the present case does not comprise laterallydisposed several conventional apparatuses but simplified mechanismsincluding an element referred to as a carrier.

BRIEF DESCRIPTION OF THE DRAWING

The above-mentioned and other objects, features and benefits of thepresent invention will be definite from the following detaileddescription in reference to accompanying drawings, in which:

FIG. 1 is a perspective view of a bag used on an apparatus;

FIG. 2 is a front view of a conventional apparatus for filling the bags;

FIG. 3 is a plan of the apparatus shown in FIG. 2;

FIG. 4 is a schematical illustrative view of an apparatus according tothe present invention;

FIG. 5 is a plan of a carrier portion;

FIG. 6 is a sectional view taken along a line VI--VI in FIG. 5;

FIG. 7 is a sectional view taken along a line VII--VII in FIG. 6;

FIG. 8 is a sectional view taken along a line VIII--VIII in FIG. 7;

FIG. 9 is a sectional view taken along a line IX--IX in FIG. 7;

FIG. 10 is a view which is seen from the direction of an arrow X in FIG.7;

FIG. 11 is a view which is seen from the direction of a arrow XI in FIG.6;

FIG. 12 is a view illustrating a device for opening and forming thebags;

FIGS. 13, 14 and 15 illustrate a filling device, and show its meteringstate, filling state and non-filling state, respectively;

FIG. 16 is a plan of a sealing device;

FIG. 17 is a sectional view taken along a line XVII--XVII in FIG. 16;

FIG. 18 is a view which is seen from the direction of the arrow XVIII inFIG. 17;

FIG. 19 is a sectional view taken along a line XIX--XIX in FIG. 17;

FIG. 20 is a view which is seen from the direction of an arrow XX inFIG. 19;

FIG. 21 is a sectional view taken along a line XXI--XXI in FIG. 19;

FIG. 22 is a sectional view taken along a line XXII--XXII in FIG. 25;

FIG. 23 is a sectional view taken along a line XXIII--XXIII in FIG. 19;

FIG. 24 is a sectional view taken along a line XXIV--XXIV in FIG. 19;

FIG. 25 is a sectional view taken along a line XXV--XXV in FIG. 17;

FIGS. 26 to 29 are views illustrating a sheet-feeding state; and

FIG. 30 is a sectional view taken along a line XXX--XXX in FIG. 16.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Now, the present invention will be described with reference to anembodiment exhibited in the drawings.

FIG. 4 shows the whole apparatus as one embodiment of the presentinvention. This embodiment comprises a six-line simultaneous carryingsystem, but the number of the carrying lines is not limited. In thedrawing, letter F represents a bag taking out and bag opening zone, G isa bag carrying zone, H is a detection zone, I is a shaping zone, J is anelimination zone, K is a filling zone, M is a sealing zone and N is adischarge zone.

Reference numeral 101 is a bag taking out device which serves to takeout the bags from a magazine 102 one by one with the aid of vacuumsuckers, turn each bag as indicated by an arrow A in the drawing, andtransfer it to a carrying member which is not shown.

Numeral 103 is a preliminary opening device. According to thispreliminary opening device, the bag 1, which has been transferredthereto from the carrying member moving along a rectangular course asindicated by an arrow B in the drawing, is sucked on the upper and lowerportions thereof by means of vacuum suckers in order to preliminarilyopen the bag 1, separating the upper and lower portions thereof fromeach other. Each bag 1 is then transferred to between a pair of grippersfor gripping the bag in a carrier, which will be described hereinafter,by a forcing member not shown, as indicated by an arrow C in thedrawing. The carrier above is carried by a pair of chain conveyors 104which are disposed in parallel and vertical planes.

Numeral 105 is a bag presence detecting device which serves to detectwhether or not the bag 1 is gripped by the grippers, with the aid of anoptical detecting means or a limit switch.

Reference numeral 106 is a bag opening and shaping device which expandsthe lower portion of each bag 1 and detects whether or not the bag 1 issurely gripped by the grippers. A detailed description of this device106 will be made hereinafter.

Numeral 107 is a defective bag eliminating device which forcedlyeliminates out the defective bag on the basis of signals from the bagpresence detecting device 105 and the bag opening and shaping device 106when the defective bag has arrived at the bag eliminating device.

Numeral 108 is a filling device which fills, with a filling material,the bags 1 in the carrier lifted by a lifting member 109 .

Numeral 110 is a sealing device which comprises a first heat sealingdevice 111, a second heat sealing device 112 and a cooling device 113.According to the sealing device, after air remaining in the bag 1 hasbeen expelled out therefrom through its opening by means of a deaeratorwhich is not shown, the bag 1 in the carrier lifted by a lifting member114 is heat sealed along the edge of its opening and, and contents inthe bag are then cooled and solidified. A detailed description of thesealing device 110 will be made hereinafter.

Numeral 115 is a discharge conveyor which is disposed crossing the chainconveyor 104 at right angles and which serves to discharge heat sealedbag products 1a toward a farther process.

Next, a carrying mechanism of the apparatus according to the presentinvention will be described.

FIGS. 5 to 11 show an embodiment of the mechanism of carrying the bags 1transferred from the above-mentioned preliminary opening device 103.

In the drawings, numeral 51 is a carrier which takes the form of arectangular parallelepiped box having such an approximately U-shapedsectional view as shown in FIG. 7. The carrier 51 is securely provided,on the opposite ends thereof, with side plates 52 and is formed with aplurality of windows 51a corresponding to the number of the carryinglines for the bags 1. Link plates 58 having lugs 57 are mounted on eachchain conveyor 104, and each lug 57 is inserted into a bearing bush 60in a guide 59 secured to the side plate 52 in order to mount the carrier51 on the chain conveyor 104 in an upward and downward movable manner. Aroller 53 rotatably and horizontally supported on each side plate 52 bya supporting shaft 54 and the like can be slidably moved within a guiderail 55 secured to a body frame not shown.

Each of shafts 62, 62a is slidably supported, via a bearing bush 64, ona guide 63 secured to the side plate 52, and is arranged so as to crossthe chain conveyor 104 at right angles. Rollers 65, 65a are mounted onend portions of the shafts 62, 62a and can roll within guide rails 66,66a. These guide rails 66, 66a are fixed to the body frame which is notshown, and an edge portion of each guide rail is folded in a widthdirection of the carrier 51, so that the shafts 62, 62a can move alongthe guide rails 66, 66a in accordance with operations of opening andclosing the bags 1.

A slider-A 67 is secured to the shaft 62a by fastening a bolt 68 and isadapted to slidably move along the shaft 62 via a bearing bush 69.Further, a slider-B 70 is secured to the shaft 62 by the bolt 68 and isadapted to slidably move along the shaft 62a via the bearing bush 69. Agripper-A 71 comprises a stationary gripper 73 fixed on the slider-A 67by a bolt 72 and the like and a rotary gripper 74 for gripping theopposite edges of each bag 1 in cooperation with the stationary gripper73. A gripper-B 71a is mounted on the slider 70, confronting theabove-mentioned gripper-A 71.

The stationary gripper 73 is fixed within a recess groove 75 (FIG. 10)of the slider-A 67 by means of a bolt 72 and is integrally and securelyprovided with a boss 73b behind it. The stationary gripper 73 isprovided, in the intermediate portion thereof, with a bracket 73c folded90° and is provided, in the front portion, with a gripping portion 73dfolded 90° in a direction opposite to the bracket 73c. Further, a plate73e for preventing a swing of the bags 1 extends downwardly from thegripping portion 73d.

A shaft portion 74a is inserted into the boss 73b of the stationarygripper 73 with the interposition of a bearing bush 77 as shown in FIG.9, therefore the rotary gripper 74 can rotatively be moved by a nut 78and the like. The rotary gripper 74 is provided, on the lower endportion thereof, with an arm 74c, is provided, in the mediate portionthereof, with a bracket 74d folded 90°, and is provided, on the upperend portion thereof, with a gripping portion 74e folded 90° in adirection opposite to the bracket 74d. Further, a plate 74f forpreventing the swing of the bags 1 extends downwardly from the grippingportion 74e.

A buffer material 79 is fixed on the gripping portion 74e of the rotarygripper 74 and can grip an edge portion of the bag 1 between the sameand the gripping portion 73d of the stationary gripper 73. A platespring 80 is disposed so that its opposite ends may be fixed to thebracket 73c of the stationary gripper 73 and the bracket 74d of therotary gripper 74 respectively, and it urges the arm 74c of the rotarygripper 74 about the shaft portion 74a in a counterclockwise directionin FIG. 7. A bush plate 81 is secured to the carrier 51 with theinterposition of a partition panel 82 in order to slidably support theshafts 62, 62a (FIGS. 5 and 6). In addition, the above-mentioned carrier51, shafts 62, 62a, slider-A 67 and slider-B 70 may be made of carbonfiber reinforced plastics.

Each bag 1 transferred from the preliminary opening device 103 isgripped between the grippers 71 and 71a in the following manner. In thefirst place, the arm 74c of the rotary gripper 74 is pushed up in adirection of an arrow Z in FIG. 7 by a push-up rod, a cam or the likewhich is not shown, thereby causing the rotary gripper 74 to clockwiserotate against the plate spring 80. After the bag has been fed tobetween the stationary gripper 73 and the rotary gripper 74, the latteris counterclockwise rotated in order to grip the bag 1 between thesegrippers. The guide rails 66, 66a are each folded in its edge portionhaving a predetermined width toward the side of the carrier 51.Therefore, when the carrier 51 has been forwarded to the bag opening andshaping device 106, the rollers 65, 65a are guided by the guide rails66, 66a to move as much as a predetermined distance toward each other,i.e. toward the carrier 51. As a result, the shafts 62, 62a movelikewise and the space between the grippers 71a, 71 is made narrow,thereby causing the bag 1 to open.

The distance between the guide rails 66 and 66a is extended at theposition of the sealing device 110, so that the space between thegrippers 71a and 71 is also extended and the opening of the bag 1 isconsequetly closed. When the carrier 51 has reached a postion above theconveyor 115, the rotary gripper 74 is clockwise rotated again to removethe bag product 1a.

As mentioned above, the carrier 51 can be slidably moved in upward anddownward directions by means of the column-like lugs 57 fixed to thechain conveyors 104. Therefore, since the lifting members 109, 114 canmove the carrier 51 up and down, it is not necessary to lift and lowerthe heavy filling device 108 and sealing device 110 any more.

Further, the distance between the grippers 71a and 71 can be varied bythe movement of the shafts 62 and 62a. Accordingly, when the bags 1 eachhaving a different size are used, the apparatus can be applied to suchbags only by varying the space between the guide rails 66, 66a.

Furthermore, moving members such as the above-mentioned carrier body 51,shafts 62, 62a, sliders 67, 70 and the like may be made of carbon fiberreinforced plastics instead of a matal such as stainless steel. As aresult, these members can be reduced in their weight to one-half or lessand still can maintain a predetermined strength. Moreover, because ofthe reduction in the weight, a capacity of driving sources such as themotor and the like can also be lowered.

Next, reference to the bag opening and shaping device will be made.

Each bag 1 transferred from the preliminary opening device 103 to thegrippers 71, 71a must be expanded to an enough degree prior to thefilling of a material. Moreover, it must be confirmed whether or not thebag 1 is surely gripped by the grippers 71, 71a. If the bag 1 is notsufficiently expanded, an amount of the filling material will be smallor the material will spill from the bag 1. Further, if the bag 1 is notsurely gripped, it will fall in transit or its sealing will beimpossible. For these reasons, it is required to dispose the bag openingand shaping device.

In FIG. 12, an embodiment of this bag opening and shaping device 106 isexhibited.

A nozzle 85 which will be airtightly thrust into the bag 1 is formedinto a shape similar to that of an opening of the bag 1 in its sectionalview. In the nozzle 85, there are provided a high-pressure compressedair passage 86 and a low-pressure air passage 87. An air pipe 88 isconnected to an upper end of the high-pressure compressed air passage 86and extends to a compressed air source which is not shown. Through thisair pipe 88, air having a pressure of 1 to 2.5 kg/cm² is fed to thenozzle 85. Further, at the lower end 85a of the high-pressure compressedair passage 86, its inner diameter is contracted. An air tube 90 isconnected to the above-mentioned low-pressure air passage 87 and extendsto a pressure detecting switch 94. This pressure detecting switch 94serves to detect a pressure of low-pressure air (generally 0.005 to 0.05kg/cm²) fed through the low-pressure air passage 87 and send an outputsignal to an electrical control circuit 83. A cover cylinder 89 isintegrally fixed to a supporting plate 99 which is secured, by means ofa bolt 98, to a duct 97 fitted to the body frame, and theabove-mentioned air pipe 88 and the air tube 90 extend through thiscover cylinder 89. Reference numeral 96 is a compression spring which isinterposed between the supporting plate 99 and a collar 92 fixed to theair pipe 88 and which always presses the air pipe 88, i.e. the nozzle 85in a downward direction. Numeral 84 is a guide pin which projects from acollar 93 integrally fixed to an upper end of the air pipe 88 and whichis inserted into an orifice 91 formed in the supporting plate 99.Therefore, the nozzle 85 can be moved up and down by the guidance ofthis guide pin 84.

According to the bag opening and shaping device 106, the bags 1 aresufficiently expanded and the bags 1 having defective openings aredetected. That is to say, the nozzle 85 supported by the duct 97 whichhas been lowered by a suitable means not shown is thrust into theopening of each bag 1 to seal it. High-pressure compressed air is thenfed to the bag 1 through the air pipe 88 connected to an air compressionsource not shown and the high-pressure compressed air passage 86 inorder to sufficiently expand the bag 1. At this time, a pressure in thebag 1 is led to the pressure detecting switch 94 through thelow-pressure air passage 87 formed in the nozzle 85 and the air tube 90.When an internal pressure not lower than a certain set and predeterminedpressure is detected by the pressure detecting switch 94, the pressuredetecting switch 94 will send a signal of "the opening being normal" tothe electrical control circuit 83. To the contrary, when a detectedpressure is lower than the predetermined level, i.e. when the bag 1 isobliquely sited and a space is thus present between the nozzle 85 andthe opening of the bag 1, the pressure detecting switch 94 will send anoutput signal of "the opening being abnormal" to the electrical controlcircuit 83.

When receiving the signal of "the opening being abnormal", theelectrical control circuit 83 of the bag opening and shaping device 106activates the defective bag eliminating device 107, whereby the bag 1 isdisengaged from the grippers 71, 71a and is then eliminated out.

Next, reference to the filling device will be made.

It is disadvantageous to discharge a material through the fillingdevice, when the grippers 71, 71a gripping no bag 1 (this fact isdetected by the bag presence detecting device 105) arrive at theposition where the filling device lies, or when the grippers 71, 71abetween which the bag 1 has already been eliminated by the defective bageliminating device 107 arrive at the position where the filling deviceis arranged. In other words, the carrier 51 is provided with pluralpairs of grippers 71, 71a as described above and a certain pair of themhas no bag 1 sometimes, therefore it is unnecessary to feed the materialto the space between the grippers having no bag, but it is necessary tofeed it to between the grippers normally having the bag 1 therebetween.

In the following, an embodiment of this filling device will be decribedin reference to FIGS. 13 to 15.

A link mechanism 21 is connected and interlocked to a suitable drivingsource not shown, for example, a driving source for the chain conveyor104. Metering cylinders 22 are provided as many as the number of thecarrying lines for the bags 1 which are carried by the chain conveyor104, and pistons 23 are reciprocated by the link mechamisme 21. In athree-way valve 24, one 24A of the respective orifices is connected tothe metering cylinder 22. Reference numeral 25 is a storage tank forstoring the filling material therein, and this storage tank isconnected, at its discharge lower end, to another orifice 24C in thethree-way valve 24. A feeding pipe 27 is connected, at its one endportion 27A, to the remaining one orifice 24B in the three-way valve 24.A return pipe 30 is connected, at its one end portion 30A, to thestorage tank 26 and is connected, at another end portion 30B thereof, tothe feeding pipe 27.

Numeral 29 is a filling nozzle which comprises two poppet valves 29A,29B, a coupling rod 29C for coupling them and lugs 29D, 29E with whichthe poppet valves 29A, 29B contact respectively, and this constitutionmeans that the filling nozzle 29 mechanically has a valve for openingand closing the end portion of the feeding pipe 27 and a valve for thereturn pipe 30 simultaneously. Further, numeral 28 is a fluid pressureactuator for reciprocating the coupling rod 29C.

Filling the bags 1 with the material is carried out by quantitativelymetering the material which is stored in the storage tank and by feedingit through the feeding pipe 27 in accordance with the followingprocedure:

As shown in FIG. 13, a rotary valve 24D is rotated by driving the linkmechanism 21 to a position where the storage tank 25 is connected to themetering cylinder 22. Afterward, the piston 23 is pulled toward theright in the drawing in order to suck the metered material into themetering cylinder 22. At this time, the filling nozzle 29 functions soas to shut the end portion of the feeding pipe 27. That is to say, thepoppet valves 29A, 29B are lifted by means of the fluid pressureactuator 28, whereby the poppet valve 29A is brought into contact withthe lug 29E.

Subsequently, as shown in FIG. 14, the rotary valve 24D is rotated so asto reach a position where the feeding pipe 27 is connected to themeterming cylinder 22, and the piston 23 is then caused to move towardthe left in the drawing in order to squeeze out the material from themetering cylinder 22 in an arrow direction in the drawing. At this time,the poppets 29A, 29B are pushed down by the fluid pressure actuator 28as shown in the drawing in order to bring the poppet valve 29B intocontact with the lug 29D. Therefore, the end portion of the feeding pipe27 is opened and, to the contrary, the connection between the returnpipe 30 and the discharge feeding pipe 27 is cut off, whereby the bag 1is filled with the material.

If the bag 1 is not gripped by the grippers 71, 71a and any bag 1 is notpresent at the end of the feeding pipe 27, the output from the bagpresence detecting device 105 and the electrical control circuit 83 willpermit the fluid pressure actuator 28 to be controlled, whereby the endportion of the feeding pipe 27 is kept closed as shown in FIG. 15. Inthis case, the material discharged from the metering cylinder 22 isreturned to the storage tank 25 through the feeding pipe 27, the fillingnozzle 29 and the return pipe 30. As will be definite from theforegoing, it depends on the fluid pressure actuator 28 whether or notthe material is fed through the feeding pipe 27, therefore the operationof stopping the link mechanism 21 is not necessary any more. Inconsequence, even in the case that the bags 1 are carried along aplurality of the carrying lines, the link mechanism 21 can always bekept moving, and the constitution of the apparatus can be extremelysimplified.

Next, the sealing device 110 will be described in detail in accordancewith an embodiment illustrated in FIGS. 16 to 29. In FIGS. 23 and 24, aheat pipe 117 is buried in a movable seal bar 116 and a compressionspring 119 is interposed between the seal bar 116 and a spring cradle118. Further, a bolt 120 is screwed in the seal bar 116. In a stationaryheat bar 121, there are buried a heat pipe 122, a cartridge heater 23and a thermocouple 124, and the stationary heat bar 121 is secured to aseal bar support 126a via a thermal insulating material 125 by means ofa bolt 127. The insulating material 25 has the same lateral length asthe seal bar support 126a and includes cutouts which allow thecompression spring 119 and the bolts 120, 127 to loosely passtherethrough.

Numerals 126a to 126c are seal bar supports each of which has a plate128 secured at its lower end portion by a bolt or the like (not shown),and between the plate 128 and the stationary heat bar 121, the movableseal bar 116 is slidably interposed. Moreover, a bolt 129 for supportingthe spring cradle 118 is screwed in the seal bar support 126a, and astepped orifice 130 is formed in the seal bar support 126a so as toallow a stem portion and a head portion of the bolt 120 to loosely passtherethrough. A thermal insulating material 131 is fixed to the seal barsupport 126a, confronting the stationary heat bar 121, by a bolt notshown. Holders 132 are secured to the opposite upper end portions of theseal bar support 126a by welding or the like, and on each of theseholders, a cam follower 133 is pivotally mounted (FIG. 19).

A rail 134 is supported on a main frame 135 via a block 136, and the camfollowers 133 are in a slidable state. A double side rail 137 isdisposed at the intermediate position 138 of the apparatus body (in thisembodiment, the intermediate position means a center of six carryinglines for the bags 1 and divides these carrying lines into two partseach including the three carrying lines) and is supported on the mainframe 135 via a block 139, and the cam follower 133 is in a movablestate. Reference numeral 140 is a guide block which is fixed to the sealbar support 126a (FIGS. 17 and 19). A support plate 141 is supported onthe main frame 135 with the interposition of a block 142 and has a camfollower 143 for guiding the guide block 140.

Numeral 144 is a stationary heat and seal bar in which a heat pipe 145,a cartridge heater 146 and a thermocouple 147 are buried, as shown inFIG. 23. Further, the stationary heat and seal bar 144 is secured to aseal bar support 151a via thermal insulating materials 148 and 149 bymeans of a bolt 150, and has the same lateral length as theabove-mentioned heat bar 121 and seal bar support 126. Numerals 151a to151c are seal bar supports each of which has a plate 152 secured theretoat its lower end portion. Further, as in the aforementioned seal barsupport 126, each of the seal bar supports 151a to 151c is provided withthe holder 132, the cam follower 133 and the guide block 140, is guidedby the rail 134, the double side rail 137 and the cam follower 143, andis adapted to move in a direction opposite to the above-mentioned sealbar support 126.

Next, a driving relation between the seal bar supports 126 and 151 willbe described in reference to FIGS. 16 and 18. Numeral 153 is a drivingshaft which is pivotally supported by stands 154, 155 and the like, witha rotational frequency of the driving shaft set to a predetermined levelby an electric motor and a reduction gear which are not shown. Numeral156 is a double side grooved cam which is integrally joined to thedriving shaft 153 by a key or the like. Numeral 157 is an upper lever,an upside end portion of which functions to cause the a cam follower(not shown) to engage with a groove 158 of the double side grooved cam156 and a downside end portion of which is integrally joined to a sleeve159 by welding or the like. The sleeve 159 is axially supported via abush 163 by a shaft 162 which is rotatably and axially held at theopposite ends thereof by brackets 160, 161 fixed on the main frame 135.

With regard to lower levers 164, their upside end portions areintegrally secured to opposite end portions of the sleeve 159 by weldingor the like and its downside end portions are coupled to couplingelements 165, which are fixed on the seal bar support 151c. With regardto the upper lever 166, its upside end portion functions to cause a camfollower (not shown) to engage with a groove 167 which is opposite tothe aforesaid groove 158 in phase, and its downside end portion issecured to a boss 168 which is integrally mounted on the shaft 162 bymeans of a key or the like. Numeral 169 is a lower lever, an upside endportion of which is fixed to a boss 168 and a downside end portion ofwhich is coupled to a coupling member 170, which is fixed to the sealbar support 126c.

Numeral 171 is a lever, an upside end portion of which is secured to aboss 168a integral with the shaft 162 and a downside end portion ofwhich is coupled to the coupling element 170. A coupling block 172 iscoupled to the seal bar support 151c by a bush 203 and a bolt 205 whichwill be described hereinafter, and is coupled to an intermediate member173 by a bolt 206. A coupling block 174 is coupled to the coupling block172 via the intermediate member 173 by the bolt 206 and serves toaccomplish the coupling of the seal bar supports 126b and 151a to eachother via the bush 203 and the bolt 205. The bushes 203 are insertedinto orifices 204 in the coupling blocks 172 and 174 and are fixed tothe seal bar supports 151c, 126b and 151a, with the bolts 205 insertedinto the orifices 204 (FIG. 30). The coupling blocks 172, 174 are in afitting relation rotatable about the bushes 203. The bolts 206 serve tofix the coupling blocks 172, 174 and the intermediate member 173. Acoupling block 175 is coupled to the seal bar support 126c by the bush203 and the bolt 205 and is coupled to the intermediate member 176 bythe bolt 206. A coupling block 177 is coupled to the coupling block 175via the intermediate 176 by the bolt 206 and serves to accomplish thecoupling of the seal bar supports 151b and 126a to each other by thebush 203 and the bolt 205. As a result, the rotation of the couplingblocks about the bushes 203 permits compensating a gap between a thermalexpansion of the heated seal bar supports 126a, 126b, 151a, 151b and acontraction of the cooled seal bar supports 126c, 151c.

Next, reference will be made to a winding operation of a heat-resistantcloth, i.e. a Teflon sheet. Numeral 178 is a delivery roll where apredetermined amount of the Teflon sheet 180 is wound about acommercially available paper tube 179 (the sheet used in this embodimenthas a width corresponding to the three bags 1). Further, the deliveryroll 178 is supported at the opposite ends thereof by holders 182 whichare fixed to the main frame 135 via brackets 181 and is adapted todeliver a predetermined length of the sheet at the time of the renewalof sealing surfaces (FIGS. 17 and 18). A Winding roll 183 is held byholders 185, 186 which are fixed to the main frame 135 via brackets 184and is adapted to wind up a predetermined length of the sheet at thetime of the renewal of the sealing surfaces. Guide bars 187 are fixed tothe rail 134, the double side rail 137 and the like and serve to guidethe Teflon sheet 180.

As shown in FIG. 19, stationary guide bars 188 are disposed between theseal bar supports 126 and 151 and are supported by a holder 189 securedto the rail 134 and another holder 190 secured to the double side rail137 on the lower surface thereof. Further, on these stationary guidebars, the Teflon sheet 180 is windingly supported.

Movable guide bars 191 are disposed between the seal bar supports 151aand 151b and between the seal bar supports 126b and 126c respectively,as shown in FIG. 17. Further, as seen in FIGS. 22 and 25, each movableguide bar 191 is supported by a holder 192 fixed to the rail 134 andanother holder 193 fixed to the double side rail 137 and is adapted towindingly support the Teflon sheet 180. The holder 192 comprises ahollow cylinder member 194, a slider 195 inserted into the cylindermember 194 slidably in upward and downward directions, a cap nut 196screwed in the lower end portion of the cylinder member 194, and acompression spring 197 disposed between the slider 195 and a spring seat198, an end portion of the movable guide bar 191 being inserted into theslider 195, whereby the above-mentioned movable guide bar 191 can moveupward and downward within a vertically extending cutout 199.

A structure of the holder 193 is the same as that of the holder 192 justdescribed with the exception that the spring seat 198 is deletedtherefrom. Incidentally, a required passing sheet length of the Teflonsheet 180 between the delivery roll 178 and the winding roll 183 variesat the times of a heat sealing (FIG. 17) and a bag opening (FIG. 20),but its varied length can be absorbed by the upward and downwardmovements of the movable guide bar 191, with the result that the Teflonsheet 180 can always maintain a stretching state. Furthermore, a sizerelation of the stationary guide bar 188, the seal bar support 126 or151 and the movable guide bar 191 is determined so that each passinglength of the sheet 180 may be equal as shown by the letters x in FIG.26.

Reference numeral 200 is a lifting lever the upper end of which iscoupled to a bracket 201 fixed to the main frame 135 and the lower endof which is connected to a driving source not shown, whereby the wholesealing device 110 can be rotated 90° about the driving shaft 153 in adirection of an arrow E in FIG. 17. The driving shaft 153 is axiallysupported at the opposite ends thereof by bearings 202 fixed to standswhich are not shown. Moreover, the movable seal bar 116, the stationaryheat bar 121 and the stationary heat and seal bar 144 which constitutethe cooling device 113 are provided with cooling members instead of theheater 123 and the like.

Reference to the behavior of the sealing device 110 will be described.In each of the first and second heat sealing devices 111, 112, as shownin FIG. 23, a surface pressure on the movable seal bar 116 is previouslyset by adjusting the bolt 129, a temperature of the stationary heat bar121 is set to a predetermined level by the use of the cartridge heater123, the heat pipe 122 and the thermocouple 124, and a temperature ofthe movable seal bar 116 is set to a predetermined level by thetransmission of heat from the stationary heat bar 121. In this case, thetemperature of the movable seal bar 116 can be uniformly distributed bythe heat pipe 117. On the other hand, the stationary heat and the sealbar 144 are also set to a predetermined temperature by the cartridgeheater 146, the heat pipe 145 and the thermocouple 147.

Next, the driving shaft 153 is rotated, and the resulting rotary motionis then converted into a linear motion of the coupling member 170,whereby the seal bar supports 126c, 151b and 126a are moved as much as adistance L toward the carrying direction D of the bags 1 with the aid ofthe coupling block 175, the intermediate member 176 and the couplingblock 177 in order to accomplish the heat sealing of the bags 1, asshown in FIG. 23. On the other hand, the seal bar supports 151c, 126band 151a are also moved as much as the length L away from the carryingdirection D of the bags 1 by converting the rotary motion of the drivingshaft 153 into a linear motion in order to carry out the cooling andthus the hardening of the heat sealed upper opening portions of the bags1, as shown in FIG. 17 (at this time, the movable seal bar 116 contractsthe compression spring 119 as much as a length l).

Before a group of the seal bar supports 126c, 151b, 126a and anothergroup of the seal bar supports 151c, 126b, 151a are advanced toward eachother by the distance L, the bags 1 are lifted as much as a distance Hwhile gripped on the carrier 51 (FIG. 17). A value obtained bysubtracting a distance h between the upper end of the unlifted bag 1 andthe lower end of the seal bar 144 from the above distance H will be awidth of the heat sealed portion of the bag 1.

After a predetermined time has lapsed, the group of the seal barsupports 126c, 151b, 126a and the other group of the seal bar supports151c, 126b, 151a are moved away from each other in order to disengagethe bags 1. The operation described above is repeated to accomplish theheat sealing, the cooling and the hardening of the bags 1 in turn.

Next, a procedure of carrying out the renewal of the Teflon sheet 180will be described in reference to FIGS. 26 to 28.

When the renewal is intended from the state of FIG. 26 to feed new sealsurfaces, the winding roll 183 is rotated to wind up as long a sheetportion as 2× of the Teflon sheet 180. The portions represented by crosssymbols in FIG. 27 are new seal surfaces. Further, at the time of a nextrenewal, a length of 2× of the sheet is likewise wound up in order tofeed new seal surfaces represented by circular symbols in FIG. 28. Atthe third renewal, a length of 14× of the sheet is wound up, so that thestate of FIG. 26 is now returned. Subsequently, the similar renewalprocedure can be repeatedly carried out.

As will be definite from the foregoing, according to the apparatus forfilling the bags of the present invention, it can be detected whether ornot the grippers disposed in the apparatus surely grip the bags.Further, in the case that the plurality of filling devices is connectedto the one link mechanism and is driven thereby, the only one fillingdevice can be stopped, when a certain bag on this filling device shouldnot be filled with the material. In consequence, it is possible toprovide the apparatus in which such a function is incorporated and asimplified structure suitable for the transit of the bags along theplural carrying lines is equipped.

What is claimed is:
 1. An apparatus for sealing bags, comprising:a pairof chain conveyors disposed in parallel vertical planes; grippers forsaid bags held on said chain conveyors; a plurality of pairs of sealbars which are disposed facing each other across openings of said bagsgripped by said grippers and which moves toward and away from said bags;guide rolls disposed above and parallel with said seal bars; aheat-resistant cloth extended between inside surfaces of said seal barsand upper surfaces of said guide rolls; and a device for sending outsaid heat-resistant cloth.
 2. An apparatus for sealing the open sealableends of bags, comprising:chain conveyor means for conveying a pluralityof bags having open sealable ends in a row and in a feed direction; afirst pair of sealing bars having facing surfaces and mounted formovement toward and away from each other parallel to the feed directionfor closing and sealing the open end of each bag; a second pair ofsealing bars positioned downstream of said first pair of sealing bars inthe feed direction, said second pair of sealing bars having facingsurfaces and being mounted for movement toward and away from each otherparallel to the feed direction for further sealing the open end of eachbag moving in the feed direction; drive means connected to said firstand second pairs of sealing bars for moving said sealing bars toward andaway from each other; a first guide bar mounted above and between saidfacing surfaces of said first pair of sealing bars; a second guide barmounted above and between said facing surfaces of said second pair ofsealing bars; a third guide bar mounted above and between one sealingbar of said first pair of sealing bars and one sealing bar of saidsecond pair of sealing bars; each of said sealing bars of said first andsecond pairs of sealing bars haivng lower guide surfaces; and heatresistant sheet feed means for feeding a heat resistant sheet across andunder said lower guide surfaces, between said facing surfaces and oversaid first, second and third guide bars.
 3. The apparatus of claim 2,wherein said first and second guide bars are fixed with respect to saidfirst and second pairs of sealing bars, said third guide bar beingmounted for vertical movement with respect to said sealing bars of saidfirst and second pairs of sealing bars, and biasing means engaged withsaid third guide bar for biasing said third guide bar upwardly to holdthe heat resistant sheet taut as said sealing bars are moved toward andaway from each other.
 4. The apparatus according to claim 2, wherein avertical distance between said first, second and third guide bars and aplane containing said lower guide surfaces are equal to each other andequal to a length of each lower guide surface in the feed direction. 5.The apparatus of claim 4, including a main frame on which said first andsecond pairs of sealing bars are mounted for movement and to which saidfirst, second and third guide bars are connected, said feed meanscomprising a first roll rotatably mounted on an axis transverse to thefeed direction and one end of said main frame with respect to the feeddirection, said first roll carrying a rolled up supply of heat-resistantsheet, and a second roll rotatably mounted on an axis transverse to thefeed direction at an opposite end of said main frame with respect to thefeed direction for rolling up heat-resistant sheet supplied by saidfirst roll.
 6. The apparatus of claim 5, wherein said chain conveyormeans comprises a pair of chain conveyors disposed in parallel verticalplanes;a plurality of grippers connected to each chain conveyor, pairsof grippers on said pair of chain conveyors holding bags therebetween.7. The apparatus according to claim 6, wherein said drive meanscomprises a main drive shaft rotatably mounted to said main frame, cammeans operatively connected between said main drive shaft and eachsealing bar for moving said sealing bars toward and away from eachother, and means for rotating said main frame about said main driveshaft for lifting said first and second rolls away from the feeddirection.
 8. The apparatus according to claim 2, including a first pairof sealing bar supports carrying said first pair of sealing bars andbeing mounted for movement toward and away from each other by said drivemeans and a second pair of sealing bar supports carrying said secondpair of sealing bars and being mounted for movement toward and away fromeach other by said drive means, one of said sealing bars of each of saidfirst and second pairs being movably mounted to its sealing bar supportand the other sealing bar of each of said first and second pairs beingfixed to its sealing bar support.
 9. The apparatus according to claim 8,including a spring engaged with each movable sealing bar for biasingeach movable sealing bar toward the fixed bar of its respective pair ofsealing bar supports.